Emission surface act like a down area light -- Not 360 degree
The way a surface responds to light depends on the direction that particular point on the surface is facing. The direction of a point on the surface is determined by the 'Normal' of that surface. The Normal can be determined either by the actual surface geometry or this can be overridden by your Normal Map.
In your particular case, the way the surface seems to be reacting to the light, the way the surface seems to be reacting to the light indicates that the normal is generally pointing 'up' and to the 'right' - ie, it's only responding to light from that direction. As this is different to the apparent geometry, this indicates a problem with the normal - especially since the problem goes away when rendering with a different wall texture.
There is a problem either with your Normal Map itself or with how you are connecting the Normal Map to your material's nodes (impossible to say without seeing either the normal map or the nodes).